Cleaning apparatus and detecting method thereof

ABSTRACT

The disclosure provides a cleaning apparatus and detecting method thereof. The cleaning apparatus includes a fan, a motor, a detecting device and a control unit. The motor drives the fan to create an air flow through the cleaning apparatus. The detecting device is electrically connected to the motor, and is utilized detected an impedance of the motor. The control unit is electrically connected to the motor and the detecting device respectively, for comparing the impedance of the motor with a predetermined value and outputting a signal indicative of a comparison result.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims priority of Taiwan Patent Application No.098116839, filed on May 21, 2009, the entirety of which is incorporatedby reference herein.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The disclosure relates to cleaning apparatus and detecting method, andin particular relates to an auto-cleaning device and detecting method.

2. Description of the Related Art

Particles detection technology is currently being used in traditionalvacuum cleaners, air cleaners, self-propelled vacuum cleaners, and cleanrooms. The detection of amount of particles and environmental control isto make cleaning more efficient. With a simple and effective way tomeasure the amount of dust and the size, the cleaning performed by thetraditional vacuum cleaners, air cleaners, or self-propelled vacuumcleaners can be more efficient, and thus it can promote environmentprotection by energy-saving and carbon emission reduction.

Known particle detection technology can be broadly divided into thefollowing three categories:

(1) Optical detection: The main principle is to use a pair of opticaltransmitter and receiver devices, where each receiver detects intensityof light emitted by the corresponding optical transmitter. In principle,the detected intensity increases when the density of dust grainsdeclines, thereby identifying the amount of dust present. For example,in U.S. Pat. No. 4,601,082, optical sensors are used to detect dust.Further, in U.S. Pat. No. 5,608,944 and U.S. Pat. No. 6,571,422,circuits of signal processing, such as amplification, filtering, andother methods, are introduced to improve the sensor's sensitivity.(2) Pressure-Difference detection: The principle determines whether thefilter needs to be replaced or the amount of waste dust collection boxis full by comparing the pressure difference between the dust collectionbox and the suction inlet.(3) Piezoelectric pressure sensing: The PZT (Lead Zirconate Titanate)pressure sensing element is placed at the inner wall of the vacuumsuction inlet. The amount of dust inhaled is determined by the pressuresapplied to the PZT pressure sensing element by the impact of dust.

BRIEF SUMMARY OF THE INVENTION

In an embodiment, the cleaning apparatus includes a fan, a motor, adetecting device, and a control unit. The motor is for driving the fanto create an air flow through the cleaning apparatus; the detectingdevice is electrically connected to the motor to detect an impedance ofthe motor; and the control unit is electrically connected to thedetecting device, for comparing the impedance of the motor with apredetermined value and outputting a signal indicative of a comparisonresult.

In another embodiment, the cleaning apparatus further includes a dustcollecting unit positioned in a path of the air flow to trap dust fromthe air, and the signal indicates a state of the dust collecting unit orfilter.

In another embodiment, the cleaning apparatus further includes a blowingdevice for directing exhaust air of the fan to a sensing surface of theat least one optical sensor.

In another embodiment, a method for debris detection in a cleaningapparatus includes measuring an impedance of a motor of a fan of thecleaning apparatus; determining a level of debris accumulation in thecleaning apparatus based on the impedance of the motor; and issuing asignal indicative of the level of debris accumulation exceeding apredetermined value.

In another embodiment, a method for debris detection in a cleaningapparatus includes arranging multiple optical sensors at differentlocations in the inlet for detecting the sensing surface at saiddifferent locations. The cleaning operation of the cleaning apparatus iscontrolled based on the determined dust covered surface areas receivedfrom said optical sensors.

While the disclosure has been described by way of example and in termsof the preferred embodiments, it is to be understood that the inventionis not limited to the disclosed embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading thesubsequent detailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 a is a perspective view of a cleaning apparatus according to anembodiment;

FIG. 1 b is an explosive view of a cleaning apparatus according to theembodiment depicted in FIG. 1 a;

FIG. 1 c is a perspective view of a cleaning apparatus according toanother embodiment;

FIG. 1 d is an explosive view of a cleaning apparatus according to theembodiment depicted in FIG. 1 c;

FIG. 2 is a circuit block diagram of a cleaning apparatus according toan embodiment;

FIG. 3 a is a block diagram of the control unit according to theembodiment depicted in FIG. 2;

FIG. 3 b is a function diagram of the band pass filter according to theembodiment depicted in FIG. 3 a;

FIG. 3 c is a block diagram of the control unit according to anotherembodiment;

FIG. 4 is a cross-sectional view of an intake of the cleaning apparatusaccording to an embodiment;

FIG. 5 is a flow chart of a detecting method of a cleaning apparatusaccording to an embodiment;

FIG. 6 is a flow chart of a detecting method of a cleaning apparatusaccording to another embodiment; and

FIG. 7 is a flow chart of a detecting method of a cleaning apparatusaccording to yet another embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The descriptions below are made to illustrate exemplary embodiments ofthe disclosure. It is noted that the drawings of the disclosure are notto scale. The drawings are intended to depict only typical aspects ofthe disclosure, and therefore should not be considered as limiting thescope of the disclosure. In the drawings, like numbering represents likeelements between the drawings.

Referring to FIG. 1 a, 1 b and FIG. 2, cleaning apparatus 1 includes ahousing 10, a fan 20, a motor 30, a detecting device 40, a control unit50, two pairs of optics sensor 60, a dust collecting unit 70, threewarning members 80, four blowing devices 90, and a driving system 110.Although, in the following illustration, cleaning apparatus 1 issometimes referred to as an auto-cleaning device, in some embodiments,cleaning apparatus 1 can be a vacuum cleaner or an air cleaning machine.Thus, other embodiments are also within the scope of the followingclaims.

The housing 10 substantially encloses the fan 20, the motor 30, thedetecting is device 40, and the control unit 50 therein. Further, thehousing 10 has an inlet 11, which has a shape of a long strip andincludes a left area 11 a and a right area 11 b.

Referring to FIG. 1 a, the motor 30 is configured to drive the fan 20 tocreate an air flow through the cleaning apparatus so that dust can besucked in through the inlet 11. The motor 30 is set below the fan 20inside the housing 10. As shown in FIG. 2, the motor 30 is coupled tothe fan 20 in order to drive the fan 20.

The detecting device 40 is disposed beside the control unit 50 and themotor 30 inside the housing 10, and is electrically connected to themotor 30 and the control unit 50, respectively, in order to detect thean impendence of the motor 30. In some embodiments, if the motor 30 is abrushless motor, the detecting device 40 is integrated into the circuitof the brushless motor.

The control unit 50 is disposed below the motor 30 inside the housing10, and is electrically connected to the motor 30, the detecting device40, and the driving system 110, respectively, in order to control theoperation of the fan 20 and the moving speed of the cleaning apparatus1. The control unit 50 is configured to compare the detected impedanceof the motor with a predetermined value and output a signal indicativeof the comparison result.

The detecting device 40 of the cleaning apparatus 1 according to atleast one embodiment is configured to detect an impedance of the motor30 for measuring debris accumulation inside a dust collecting unit. Thedust collecting unit could include a filter 72 and a box 71. Theimpedance of the motor 30 increases when the debris accumulation insidethe dust collecting unit or the blockage of the air outlet and inletincreases. When the voltage of the motor 30 is fixed, it leads to thedecrease of the current and increase of the resistance. The resistanceof the motor 30 can be measured after the current value of the motor 30detected by the detecting device 40. In some embodiments, the detectingdevice is a current detecting device that detects a current value of thefan. When the detecting device detects a current value that is below apredetermined current value, the control unit 50 may stop driving themotor 30.

As shown in FIG. 3 a, in at least one embodiment, the control unit 50including a band-pass filter 51, an amplifier 52, a pulse expander 53,an analog/digital converter 54, and a micro controller 55. The band-passfilter 51 is a multi-level filter circuit that is configured to removethe electronic noise from other components (e.g. the motor 30). In oneembodiment, as FIG. 3 b shown, the band-pass filter 51 is a four-levelfilter circuit, including a high-pass filter 51 a, a low-pass filter 51b, a band-pass circuit 51 c, and a wave-shaping circuit 51 d. In someembodiments, regarding the band-pass filter 51, the gain is 2±3%, thecentral frequency is 110 kHz±3%, the bandwidth of 3 dB is 90 kHz±3%, andan electronic bandwidth is 20 kHz˜200 kHz. It should be realized thatalthough the embodiment disclosed herein is a four-level filter circuit,it is not limited to such design. Any other circuit design is workableas long as the gain, central frequency, 3 dB bandwidth, and electronicbandwidth comply with standards previously stated.

Referring to FIG. 3 a, the amplifier 52 amplifies signals from theband-pass filter 51; the pulse expander 53 adjusts the samplingfrequency of signals from other components (ex: optical sensor 60); theanalog/digital converter 54 performs a analog/digital conversion forsignals from other components; and the micro controller 55 utilizessignals processed by the analog/digital converter 54 to control thesuction and the moving speed of the cleaning apparatus 1. Furthermore,in some embodiments, it is also desirable to utilize PWM (Pulse WidthModulation) to control the suction and the moving speed stated above.When the cleaning apparatus 1 detects a rather dusty condition, it willbe adjusted to have a stronger suction power and slower moving speed,therefore improving the cleaning efficiency.

It should be realized that internal configuration of control unit 50 isnot limited to the way FIG. 3 a shown. Any configuration accomplishedsubstantially the same result is desirable. For example, FIG. 3 c showsanother example of the control unit. The control unit 50′ includes twoband-pass filters 51, two amplifiers 52, a pulse expander 53, ananalog/digital converter 54, a micro controller 55, and a comparator 56.The difference between the control unit 50′ in FIG. 3 c and the controlunit 50 in FIG. 3 a is that the control unit 50′ further includes acomparator 56. The comparator 56 compares the signal after the suctionoperation is commenced with the signal before the suction motion iscommenced.

Referring to FIG. 1 a, two pairs of optical sensors 60 are disposedinside the inlet 11 of the housing 10, in order to detect the amount ofduct passing though the inlet. While the surface area of any of the twooptical sensors 60 is covered by dust over a predetermined percentage(ex: over 90%), the control unit 50 ceases the motor 30 that drives thefan 20. The two optical sensors 60 are separately disposed on the leftarea 11 a and the right area 11 b inside the inlet 11. It should berealized that although the embodiment disclosed herein utilizes twooptical sensors, the number of optical sensor is not limited to two, andit's also desirable to change the number of optical sensors used.

As FIG. 4 shown, each optical sensor 60 comprises a transmitter 61 and areceiver 62, wherein the transmitter 61 and the receiver 62 are placedfacing each other inside the inlet 11. It is realized that the locationof transmitter 61 and receiver 62 is not limited to what figuresillustrated. Referring FIG. 1 c and FIG. 1 d, in some embodiments, thetransmitter 61 and receiver 62 are disposed in a manner that they bothface the same direction. In that case, the receiver 62 receives signalsfrom the transmitter 61 by reflection.

Referring FIG. 1 a, the dust collecting unit 70, which is positioned ina path of the air flow to trap dust from air inhaled by to the fan 20,comprises a box 71 and a filter 72. When the control unit 50 ceases themotor 30 that drives the fan 20, the dust collecting unit 70 isconfigured to be cleaned up. That is, the box 71 is cleaned and/or thefilter 72 is replaced by another one.

Referring FIG. 2 is a circuit block diagram of the cleaning apparatus.There are three warning members 80 disposed on the housing 10 andelectrically connected to the control unit 50. The warning member 80 isactivated (e.g. switched on) by the control unit 50 when the signalindicates that the impedance of the motor is higher than thepredetermined value. In some embodiments, three warning members 80 maybe light emitting diodes respectively and can emit light when switchedon by the control unit 50. In some other embodiments, the warning member80 can be buzzers, indicators, or other devices according to variousapplications. Also, although only three warning members 80 are depictedfor an exemplary embodiment, the number of the warning members 80 can bemore or less than three.

FIG. 4 is a cross-sectional view of an intake of the cleaning apparatusaccording to an embodiment. In some embodiments, there are two blowingdevices 90 is for directing exhaust air from the fan 20 to a sensingsurface of the at least one optical sensor (not shown in figures) toblow dust off said sensing surface for preventing the optical sensor 60from being affected by the dust coverage. Each blowing device containsone air outlet 90 a. The two air outlets 90 a respectively located underthe transmitter 61 and the receiver 62. The two blowing devices 90 areseparately connecting to the air outlet (not shown in figures) of thefan 20. The a portion of air-exhaust of the fan 20 is guided to andblows through the air outlet 90 a to the transmitter 61 and the receiver62 for cooling the transmitter 61 and /or the receiver 62 and reducingthe coverage of the dust. Each of the blowing devices 90 includes avalve 91 as depicted in FIG. 1. The valve 91 electrically connected withthe control unit 50 to control the exhaust air flowing through theblowing device 90. The air outlet 90 a can be located under thetransmitter 61 and the receiver 62 in this exemplary embodiment of FIG.4. The air outlet 90 a can also be located on the side part of thetransmitter 61 and the receiver 62. The location of air outlet 90 a canbe adjusted as long as the exhaust air of the air outlet 90 a can blowto the transmitter 61 and the receiver 62.

The driving system 110 for moving the auto-cleaning device is disposedon the housing 10, connected to the fan 20 and the motor 30 in the wayas depicted in FIG. 1 a, and electrically connected with the controlunit 50 in the way as depicted in FIG. 2. Note that the arrangement ofevery element in the housing are not limited to these embodimentsdepicted by the figures.

Referring to FIG. 5, it is a flowchart of a detecting method of thecleaning apparatus. The step of method comprises: turning on the powerof the cleaning apparatus 1(S11), measuring the impedance of the motor30 by the detecting device 40(S12), determining a level of debrisaccumulation in the cleaning apparatus 1 based on the impedance of themotor 30(S13). When the level of debris accumulation exceeds apredetermined value, the process proceeds to Step S14. Then, a signalindicative of the level of debris accumulation exceeding a predeterminedvalue is issued (in one or more embodiments to the warning member 80such as light emitting diodes or buzzers), and stop the motor 30(S14).Then, the power of the cleaning apparatus 1 is turned off and the dustcollecting unit 70 is cleaned (S15).

In one embodiment, Step 4 (S14) is to issue a signal when the level ofdebris accumulation reaches 80% of the space inside the box 71. Thepredetermined percentage value of the space inside the box 71 can beadjusted according to various applications.

In one or more embodiments, to decide when to clean the dust collectingunit 70 by using the impedance value of the motor 30 can improve theefficiency of the cleaning apparatus 1.

There are three warning members 80 are disposed on the housing 10, andelectrical connected with the control unit 50. When the control unit 50determines that motor 30 for the fan 20 need to be stopped, the controlunit 50 activates one or more warning members 80. In some embodiments,the warning members 80 are light-emitting diodes. When the control unit50 activates one or more warning members 80, the light-emitting diodes(i.e. the warning members 80 being activated) emit light. Although onlythree warning members 80 are depicted in the exemplary embodiment, insome other embodiments, there can be more or less than three warningmembers 80 disposed on the housing 10. Further, the warning members 80disclosed in the exemplary embodiment are light-emitting diodes.However, in some other embodiments, the warning members 80 can belight-emitting diodes, buzzers, other indictors, and/or combinationthereof.

FIG. 6 is a flowchart of an embodiment of a detecting method in acleaning apparatus. The detecting method comprises some steps asfollows. First, power the cleaning apparatus 1 on in step S21. Next, instep S22, detect the amount of dust passing through an inlet 11 of thecleaning apparatus 1 and a sensing surface of an optical sensor 60 bythe optical sensor 60. After that, in step S23, determine a dust coveredsurface area of the optical sensor 60. In detail, optical sensor 60senses the status of the sensing surface. When a percentage of thesensing surface which dust covered exceed a predetermined value, such as90% in some embodiments, the optical sensor 60 outputs a sensing signalto the control unit 50, then go to step S24. In an embodiment, thesensing surface may separate to several equal grids. By counting thenumber of the grids which dust covered on the sensing surface, it mayobtain the percentage to determine a dust or garbage covered surfacearea of the optical sensor. In some embodiments, a cleaning operation ofthe cleaning apparatus is controlled based on the determined dustcovered surface area. In step S24, when the control unit 50 receives thesensing signal, the motor 30 is stopped and a warning member 80 isactivated. Finally, power off the cleaning apparatus 1 and clean a dustcollecting unit 70 of the cleaning apparatus 1 in step S25.

Before the step S23, in some embodiments, a blowing device 90 can beactivated and used to blow exhaust air of the fan 20 at the sensingsurface of the optical sensor 60 before said determining the dustcovered surface area to decrease the amount of dust or garbage coveredon the sensing surface of the optical sensor 60. It may prevent thesensitivity of the optical sensor 60 from degrading. In addition, in atleast one embodiment, the predetermined value is 90%, but thepredetermined value may change in various applications. It is notlimited hereto.

The detecting method in a cleaning apparatus which said before maydetermine when to clean the dust collecting unit 70 of the cleaningapparatus 1 by detecting status of the sensing surface of the opticalsensor 60. It may increase the efficiency of the cleaning apparatus 1when the cleaning apparatus 1 is working.

FIG. 7 is a flowchart of another embodiment of a detecting method of acleaning apparatus. In an embodiment, the detecting method may apply toan auto-cleaning device. The auto-cleaning device comprises multipleoptical sensors arranged at different locations in the inlet fordetecting the sensing surface at said different locations. Take FIG. 1 cand FIG. 1 d for example, there are two optical sensors 62′ and 61′arranged at a left area 11 a and a right area 11 b of the inlet,respectively, and a cleaning operation of the cleaning apparatus 1 iscontrolled based on the determined dust covered surface areas receivedfrom said optical sensors 60′. The detecting method comprises some stepsas follows. First, in step S31, power the cleaning apparatus 1 on. Whena dust collecting unit 70 of the cleaning apparatus 1 needs not to becleaned, the cleaning apparatus 1 remains in a walking mode. Next, instep S32, detect the amount of dust passing through an inlet 11 of thecleaning apparatus 1 and sensing surfaces of the optical sensors 62′ and61′ by the optical sensors 60′. Then, compare with the determined dustcovered surface areas received from the optical sensors. In anembodiment, the cleaning apparatus 1 turns to a direction where anoptical sensor has a dust covered surface area larger than anotheroptical sensor in step S33. For example, when the determined dustcovered surface area of the optical sensor 62′ at the left area 11 alarger then the determined dust covered surface area of the opticalsensor 61′ at the right area 11 b, the cleaning apparatus 1 turns left.On the contrary, when the determined dust covered surface area of theoptical sensor 61′ at the right area 11 b larger then the determineddust covered surface area of the optical sensor 62′ at the right area 11a, cleaning apparatus 1 turns right. In addition, the cleaning operationof the cleaning apparatus 1 further adjusts at least one suction powerand/or a moving speed of the cleaning apparatus 1 in said direction.

Before the step S32, a blowing device 90 may be activated to blowexhaust air of the fan 20 at the sensing surface of the optical sensors60′. It may prevent the sensitivity of the optical sensors 60′ fromdegrading. Furthermore, in some embodiments, when the cleaning apparatus1 turns to said direction, a turning radius of the cleaning apparatus 1is equal to a length of the inlet 11.

By the detecting method in a cleaning apparatus set forth above, thecleaning apparatus may decide which side is dirtier based on determineddust covered surface area of the optical sensors 62′ and 61′ at the leftarea 11 a and the right area 11 b respectively. It may increase thecleaning efficiency of the cleaning apparatus 1.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A cleaning apparatus, comprising: a fan; a motor for driving the fanto create an air flow through the cleaning apparatus; a detecting deviceelectrically connected to the motor to detect an impedance of the motor;and a control unit electrically connected to the detecting device, forcomparing the impedance of the motor with a predetermined value andoutputting a signal indicative of a comparison result.
 2. The cleaningapparatus as claimed in claim 1, further comprising: a dust collectingunit positioned in a path of the air flow to trap dust from the air,wherein the signal indicates a state of the dust collecting unit or thefilter.
 3. The cleaning apparatus as claimed in claim 2, furthercomprising: an indicator electrically connected to the control unit tobe activated by the control unit when the signal indicates that a volumeoccupied by dust inside the dust collecting unit has reached apredetermined level.
 4. The cleaning apparatus of claim 1, furthercomprising: a housing receiving the fan and having an inlet for the airflow; and at least one optical sensor disposed in the inlet of thehousing to detect the amount of dust passing through the inlet; whereinthe at least one optical sensor and the control unit are configured todetermine a dust covered surface area of the at least one opticalsensor.
 5. The cleaning apparatus as claimed in claim 4, furthercomprising: a blowing device for directing exhaust air from the fan to asensing surface of the at least one optical sensor to blow dust off thesensing surface.
 6. The cleaning apparatus as claimed in claim 5,wherein the blowing device comprises an air outlet located under theoptical sensor.
 7. The cleaning apparatus as claimed in claim 5, furthercomprising: a valve electrically connected to the control unit forcontrolling the exhaust air flowing through the blowing device.
 8. Thecleaning apparatus as claimed in claim 4, wherein said at least oneoptical sensor comprises multiple optical sensors positioned atdifferent locations in the inlet for detecting dust levels at saiddifferent locations, the control unit being electrically connected tosaid optical sensors for controlling a cleaning operation of thecleaning apparatus based on the detected dust levels received from saidoptical sensors.
 9. The cleaning apparatus as claimed in claim 1,wherein the control unit comprises a band pass filter leaching off theelectrical noise from the motor.
 10. The cleaning apparatus as claimedin claim 9, wherein the band pass filter is a multi-stage circuit havinga gain of 2±3%, a center frequency at 110±3% Hz, a 3±3% dB bandwidth of90±3% kHz, and an electronic bandwidth from 20 kHz to 200 kHz.
 11. Thecleaning apparatus as claimed in claim 1, wherein the control unitcomprises a pulse extension device for adjusting a sampling frequency ofthe signal from the detecting device.
 12. The cleaning apparatus asclaimed in claim 1, further comprising: a warning member to be activatedby the control unit when the signal indicates that the impedance of themotor is higher than the predetermined value.
 13. A method for debrisdetection in a cleaning apparatus, said method comprising: measuring animpedance of a motor of a fan of the cleaning apparatus; determining alevel of debris accumulation in the cleaning apparatus based on theimpedance of the motor; and issuing a signal indicative of the level ofdebris accumulation exceeding a predetermined value.
 14. The method asclaimed in claim 13, further comprising: stopping the motor in responseto said signal.
 15. The method as claimed in claim 13, furthercomprising: determining a dust covered surface area of an opticalsensor, and controlling a cleaning operation of the cleaning apparatusbased on the determined dust covered surface area.
 16. The method asclaimed in claim 15, further comprising: blowing exhaust air of the fanat the sensing surface of the optical sensor before said determining thedust covered surface area.
 17. The method as claimed in claim 15,further comprising: arranging multiple optical sensors at differentlocations in the inlet for detecting the sensing surface at saiddifferent locations; wherein the cleaning operation of the cleaningapparatus is controlled based on the determined dust covered surfaceareas received from said optical sensors.
 18. The method as claimed inclaim 17, wherein said controlling comprises: turning the cleaningapparatus to a direction of the optical sensor with the determined dustcovered surface areas larger than those determined by the other opticalsensors.
 19. The method as claimed in claim 18, wherein said controllingfurther comprises: adjusting at least one of suction power and a movingspeed of the cleaning apparatus in said direction.
 20. The method asclaimed in claim 18, wherein a turning radius of the cleaning apparatusis equal to a length of the inlet.
 21. A cleaning apparatus, comprising:a housing having an inlet; a fan within the housing for creating an airflow into the housing through the inlet; at least one optical sensordisposed in the inlet of the housing to determined a dust coveredsurface area of a sensing surface of the at least one optical sensor;and a blowing device for directing exhaust air of the fan to the sensingsurface of the at least one optical sensor to blow debris off saidsensing surface.